esm: loader hook URL validation and error messages

PR-URL: https://github.com/nodejs/node/pull/21352
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>

2 files changed, 17 insertions, 0 deletions

diff --git a/test/fixtures/es-module-loaders/loader-invalid-format.mjs b/test/fixtures/es-module-loaders/loader-invalid-format.mjs
new file mode 100644
index 0000000000..17a0dcd04d
--- /dev/null
+++ b/test/fixtures/es-module-loaders/loader-invalid-format.mjs
@@ -0,0 +1,8 @@
+export async function resolve(specifier, parentModuleURL, defaultResolve) {
+  if (parentModuleURL && specifier === '../fixtures/es-modules/test-esm-ok.mjs') {
+    return {
+      url: 'file:///asdf'
+    };
+  }
+  return defaultResolve(specifier, parentModuleURL);
+}
diff --git a/test/fixtures/es-module-loaders/loader-invalid-url.mjs b/test/fixtures/es-module-loaders/loader-invalid-url.mjs
new file mode 100644
index 0000000000..12efbb5021
--- /dev/null
+++ b/test/fixtures/es-module-loaders/loader-invalid-url.mjs
@@ -0,0 +1,9 @@
+export async function resolve(specifier, parentModuleURL, defaultResolve) {
+  if (parentModuleURL && specifier === '../fixtures/es-modules/test-esm-ok.mjs') {
+    return {
+      url: specifier,
+      format: 'esm'
+    };
+  }
+  return defaultResolve(specifier, parentModuleURL);
+}